Obesity presents an increasingly important modifiable cancer-related risk factor for populations, yet little is known about the ways to prevent and control obesity for ethnically diverse populations. Pacific Islanders experience high rates of obesity and cancer, presenting an opportunity for exploration leading to intervention development and testing, yet they remain invisible and understudied to the academic community. This two year exploratory study seeks to understand the obesity-related influences for Pacific Islander (PI) youth in Southern California. Using a Community-Based Participatory Research (CBPR) approach involving four community-based agencies and three universities, the goals of this project are to: 1) to test the feasibility of various quantitative and qualitative data collection activities among Marshallese, Samoan and Tongan adolescents; and 2) estimate the point prevalence of obesity and physical activity. A sub-aim is to explore the distribution of dietary intake in these groups; and 3) explore the predisposing, enabling and reinforcing factors influencing physical activity in this group. The specific aims of the study are: a.) Convene quarterly meetings of the Community Advisory Committee (CAC) throughout the conduct of this study to inform the development and implementation of all study methods and community outreach activities; b.) Design and facilitate focus groups with PI adolescents, aged 14-18 years, from three Pacific Islander populations (Marshallese, Samoans and Tongan) to explore influences on obesity and physical activity: i. Types of physical activity performed, including location, frequency and purpose; ii. Cultural factors, including identity, acculturation and cultural beliefs; iii. Environmental issues that present enabling opportunities and barriers to adolescents; iv. Individual factors, including predisposing and reinforcing influences; c.) Implement protocols for collection of objective measures of obesity and physical activity among adolescents: i. Height and weight for calculations of body mass index; ii. Accelerometer data for calculations of time spent in moderate and vigorous intensity physical activities; d.) Design and/or pretest a survey instrument to assess: I. Predisposing and reinforcing influences on adolescent physical activity; (also listed in b iv) ii. Dietary intakes via food frequency questionnaire (FFQ) to allow exploration of relationship between diet, physical activity and obesity among PI adolescents; e.) Implement measurement and survey activities among a community-sample of Marshallese, Samoan and Tongan adolescents in Southern California; f.) Share study results with the CAC and community members to develop future research and intervention plans. The community participatory processes, along with protocols and instruments developed, will help ensure that the preliminary study results can be expanded upon in larger-scale assessment and intervention studies for the future. [unreadable] [unreadable] [unreadable] [unreadable]